Answer: 
Step-by-step explanation:
To find the inverse of a function start by replacing f(x) with x and replace the original x with y.

Now solve for y

Finally, replace y with the inverse of f(x), 
60 divided by 0.4(40%)=150
=150
F(x) = 4 - x² g(x) = 6x
(g - f)(x) = g(x) - f(x)
(g - f)(3) = g(3) - f(3)
g(x) = 6x
g(3) = 6*3 = 18
f(x) = 4 - x²
f(3) = 4 - 3² = 4 - 9 = -5
(g - f)(3) = g(3) - f(3) = 18 - (-5) = 18 + 5 = 23
(g - f)(3) = 23
Since as of now we're saying that the probability of having a girl is 1/2, we can say:
1/2 * 1/2 * 1/2 * 1/2, because then you're saying a one half chance of having a girl times another one half chance of having a girl, etc.
That ends up to be 1/16.